Rapidly interpretable signals for the interaction of coenzymes (NAD ion and NADH), effectors, and substrates with enzyme and of coenzymes and effectors with enzyme-substrate covalent intermediates have been developed, for the enzyme Glyceraldehyde-3-PO4-Dehydrogenase (GPDH). Most of these techniques are extendable to other enzymes, particularly other dehydrogenases, and in general, to other adenine nucleotide binding enzymes. We are now examining Liver Alcohol Dehydrogenase and Phosphoglycerate Kinase. The catalytic sequence in GPDH involves effector-mediated-coenzyme requiring formation of enzyme-substrate compound (acyl enzyme), followed by effector-mediated phosphorolysis of the acyl-enzyme. The system responds to both positive and negative effectors. The ligand-dependent covalent nature of the acyl-enzyme bond can be monitored. Thus, extensive molecular and bonding details, as well as information relating to the sequence of ligation and reaction events, are obtainable from rapid transient experiments. Such a study of ligand-effected reaction sequence is relevant to more complex studies of regulation (and inter-enzyme communication) in an organized metabolic pathway, in this case, glycolysis. It is proposed to extend the ligand-specific transient methods developed to other enzyme-substrate systems and to more complex reactions involving multiple (coupled) enzymes. The mechanisms of cooperativity and "anti-cooperativity" (and "half-site" reactivity) in ligand binding to oligomeric enzyme sites are necessarily examined in such investigations.